1. Field of the Invention
The present invention is related to methods and apparatus for determining shale plasticity, and more particularly, to methods and apparatus for estimating the occurrence of petroleum drilling conditions likely to cause balling up of a drill bit during drilling of a wellbore.
2. Discussion of the Related Art
Determining clay volume, type, and water content from well logs is common practice today. However, such measurements have historically been made Independently of one another with the primary purpose of characterizing the geology of petroleum reservoirs. Although the methods measure clay parameters individually, the methods have not previously been combined to provide a measure of shale plasticity.
A measure of shale plasticity is thus desired for use in petroleum drilling operations to identify potential plastic shale zones.